High-energy wide- and small-angle scattering at 1-ID

This probe utilizes high-energy x-rays (E=50-120 keV) to investigate materials in a transmission geometry. Temporal and spatial resolution benefits from (1) a 3rd generation synchrotron source and undulator, (2) an efficient high-energy monochromator and (3) refractive focusing lenses. When combined with area detectors, this permits collection of 2-d (anisotropic) scattering information.

 

Side-view schematic of simultaneous SAXS/WAXS camera at 1-ID, with refractive lenses providing vertical focusing. Also shown are optional imaging and flourescence modes, and position of optional high-resolution monochromator. Distances are in m (not to scale).

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Recent publications:

(1) Allen, A.J., T.A. Dobbins, J. Ilavsky, F. Zhao, A. Virkar, J. Almer, and F. DeCarlo. "Characterization of solid oxide fuel cell layers by computed x-ray microtomography and small-angle scattering", in Ceramic Engineering and Science Proc., Cocoa Beach, FL, 25[3], pp. 275-280 (2004).

(2) Wang, X.-L., J. Almer, Y.D. Wang, J.K. Zhao, C.T. Liu, A.D. Stoica, D.R. Haeffner, and W.H. Wang, "In-situ synchrotron study of phase separation in bulk metallic glass by simultaneous diffraction and small angle scattering measurements", Physical Review Letters, 91(26), pp. 265501-4 (2003).

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Current Instrument Specifications (unless noted, these are quoted for an x-ray energy of 80 keV):

  • SAXS range: 0.004 < |Q=4*pi*sin(th)/lambda| < 0.2 1/A .
    • Note that when using in combination with a wide-angle detector Qmax can be extended to approximately 10 1/A.
  • SAXS detectors:   Princeton Instruments CCD or Bruker6500 CCD
  • WAXS detectors: Mar345 Image Plate or Bruker6500 CCD
  • X-ray energy (keV):   50 < E < 120 (80.7 keV typical)
  • Probe volume = S*t , where t is the sample thickness along the beam and S is the transverse beam size:
    • 1.5(H) x 0.7(V) < S < 0.01(H) x 0.002(V) mm^2
    • For wide-angle measurements the conical slit assembly can be used to provide a longitudinal resolution of ~0.1mm.
  • Incident beam flux:  
    • Io ~ 1.5e12 ph/s/mm2 (no refractive lenses)
    • Io ~ 1e10 ph/s (at Smin)
  • 1/e attenuation lengths (for estimating t(max)):
    • Al = 18 mm; Fe = 2.1mm; Zr = 0.89mm; W= 0.2mm
    • Note that due to the high incident flux, acceptable scattering patterns can often be collected even at high sample attenuation (>95%).
    • A complete list of elemental (and some compound) attenuation data versus energy can be found at the NIST website

     

Last updated: July 17, 2009